1. Technical Field
The present invention relates to an electrode to which a probe contacts, with which it is possible to avoid inconveniences associated with operations using a probe device such as characteristics measurements of electronic devices and data-input into IC parts. The invention also relates to an electronic device thereof.
2. Related Art
In a field of a mobile communication terminal device, many manufactures promote module packaging of components by function in consideration of factors including utility in implementation of electric components, repair and maintenance, handleability, components compatibility among devices and the like. With increasing demands for this module packaging, downsizing and cost cutting of components are strongly requested.
Particularly, circuit components of a reference oscillator, a phase-locked loop (PLL) circuit, a synthesizer circuit and the like are often packed in modules because functions and mechanical structures of these circuits are well established, and high stability and performance in operation are requested for these circuits. Moreover, when components of such circuit are packaged in a module, there is an advantage that a shield structure can be easily built.
An example of the electronic component that is mounted on a surface and made up of related parts which can be packaged and made into modules are a piezoelectric resonator, a piezoelectric oscillator, a surface acoustic wave (SAW) device and the like. In order to further minimize the size of the electric component as well as to keep the high performance, for example, a module having a two-story structure shown in FIG. 6 has been proposed.
JP-A-2000-278047 is a first example of related art, and Japanese Patent No. 3,406,845 is a second example of the related art. Japanese Patent No. 3,451,018 is a third example and JP-A-2004-320420 is a fourth example of the related art.
FIG. 6A is a plan view of a hitherto known piezoelectric device (quartz crystal oscillator) which will be mounted on a surface in the form of the two-story structure module (H-type). FIG. 6B is a schematic longitudinal view of the piezoelectric device and FIG. 6C is a bottom view of the piezoelectric device. A quartz crystal oscillator A includes a case (package) 101 made of ceramic, a metal lid 102, a quartz crystal resonator 100, a case (package) 105 and a bottom structure (IC part unit) 107. The quartz crystal resonator 100 includes a quartz crystal resonator element (piezoelectric element) 103 which is coupled to an element mounting pad 104 through conductive adhesive 104a. The element-mounting pad 104 is provided in a space (an upper-side concave portion) 101a between the case 101 and a metal lid 102. The quartz crystal resonator element 103 includes an exiting electrode 103b which is provided respectively on the both sides of a crystal substrate 103a. An IC part mounting electrode 105c is provided on the ceiling plane of a space (a lower-side concave portion) 105a situated in the case (package) 105 that is coupled to the bottom face of the quartz crystal resonator 100. An IC part 106 including an oscillation circuit, a temperature compensated circuit and the like is barely implemented on the IC part mounting electrode 105c in the bottom structure (IC part unit) 107. A mounted terminal 105b provided on the bottom of the case 105 is used to solder the quartz crystal oscillator A in order to implement the oscillator onto a print substrate (see the first example).
The quartz crystal oscillator A has two monitor electrodes (probe contacting electrodes) 110 for adjusting (measuring) a frequency of the quartz crystal resonator element 103 and for simultaneously checking the characteristics of the quartz crystal resonator element 103. Referring to FIG. 6B and FIG. 6C, the monitor electrodes 110 are provided on the ceiling plane of the space 105a and on one side of the longitudinal direction of the ceiling plane. The monitor electrodes 110 will be covered by the IC part when the IC part is mounted (see the first and second examples). An adjustment operation is performed by making two probe pins (contacting members) 120 contact with the monitor electrodes 110 before the IC part is mounted. The crystal oscillating element is excited and oscillates when the probe pins conductively contact with the monitor electrode 110, and the frequency of the oscillation can be measured in this way. Where the obtained figure of the frequency dose not lie in the targeted frequency range, the frequency can be adjusted by for example increasing the film thickness of the exiting electrode on the crystal oscillator element.
The quartz crystal oscillator A can be assembled in the following way. After the quartz crystal resonator element 103 is firstly mounted in the case 101, the probe pins 120 are then made contact with the two monitor electrodes 110 that are placed in the space 105a of the case 105 so as to check the characteristics of the quartz crystal resonator element 103 and to perform the adjustment of the quartz crystal resonator element 103. After the adjustment is made, the upper-side concave portion 101a is sealed with the metal lid 102. The IC part 106 is subsequently flip-chip mounted on the IC part mounting electrode 105c in the space 105a. 
Meanwhile, before the terminals of the IC part 106 are coupled onto corresponding IC part mounting electrodes 105c in the flip-chip way with a conductive bump, it is necessary to harden the IC part mounting electrode 105c by applying pressure. By hardening the IC part mounting electrode 105c, the terminal of the IC part 106 can be appropriately coupled to the mounting electrode 105c because the ultrasonic vibration energy given to the conductive bump can be transferred to the IC part mounting electrode 105c without loss. In this example, the IC part mounting electrode 105c and the monitor electrode 110 are simultaneously formed and made of the same material so that the monitor electrode 110 is also made hard. More specifically, where the IC part mounting electrode 105c and the monitor electrode 110 are formed on the ceiling plane of the space 105a which is made of ceramic, tungsten in paste form is printed on the ceramic (green-sheet) face, the printed tungsten is then pressed and hardened by a pressing means. The hardened tungsten and the ceramic are calcined at the same time and then planarized.
On the other hand, the end part of the probe pin 120 which contacts with the monitor electrode is made of a relatively hard metal material such as beryllium copper of which surface is gold-plated. When such probe pin repeatedly contacts with the hard monitor electrode, not only the gold-plated layer but also the beryllium copper part wears out. This wearing changes the contact resistance between the probe end and the monitor electrode, and the conductivity between them is deteriorated. In this case, the property of the quartz crystal resonator element cannot be properly measured. Therefore, the probe pin has to be frequently replaced with a new one and this decreases the production efficiency.
In addition to the monitor electrode, the same problem can occur to an electrode which is formed outer face of the package of the surface-mount type piezoelectric oscillator and through which data is inputted into the IC part by contacting the probe. Moreover, a mounted terminal is formed at the bottom of the package in order to monitor the frequency of a packaged surface-mounting type quartz crystal resonator. The same problem of wearing out can occur to the mounted terminal if the probe repeatedly contacts with the terminal. Furthermore, the same problem can also happen at a monitor electrode formed on the outer face of the package so as to monitor the characteristics of a SAW resonator.
The same problem can occur to any electrodes provided in any surface-mounting type electronic devices for measuring characteristics or for data input and to which a probe contacts in addition to the piezoelectric device.
In the hitherto known surface-mounting type electronic devices, where the electrode (the probe contacting electrode) used for measuring characteristics of the element included in the package or for writing data into the IC part is hardened or made solid, the metal material of the probe end where contacts with the electrode wears out in a short time period and the conductivity between the probe and the electrode deteriorates. For this reason, the probe has to be frequently replaced by a new one.